Gas discharge lamp circuit with resistive ballast and inductive ballast in parallel



Sept. 1, 1970 A. G. J. HUYGHE 6 GAS DISCHARGE LAMP CIRCUIT WITH RBSISTIVE BALLAST AND INDUCTIVE BALLAST IN PARALLEL Filed April 4, 1968 m m\\ p w United States Patent "ice 3,526,806 GAS DISCHARGE LAMP CIRCUIT WITH RESIS- TIVE BALLAST AND INDUCTIVE BALLAST IN PARALLEL Albert Gaston Joseph Hnyghe, 13 Place du General de Gaulle, Hazebrouck, Nord, France Filed Apr. 4, 1968, Ser. No. 718,875 Claims priority, application France, June 9, 1967, 109,888; Oct. 31, 1967, 126,526 Int. Cl. Hb 41/08, 41/18 US. Cl. 315100 2 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a device for regulating the lighting of fluorescent tubes. More precisely, a normal fluorescent tube may be in service (maximum light flux) or out of service (zero flux); the invention adds a mode of operation with an intermediate light flux which can be regulated when so desired.

It is frequently desirable, if not necessary, to have available a source of light, the lighting intensity of which can be varied in dependence on requirements or circumstances. In this connection, the conventional switch is a well-known mechanical means providing only all or nothing. In certain cases, for reason of safety, rapid action, economy, comfort or indication, it is not possible to be content with this, as the option should be all or reduced. This is the case for the rooms of children or sick persons, for certain corridors, passages or shops, for the cabins of lifts and for certain illuminated signs with variable or blinking effects.

The invention has therefore for its object a supply device for a fluorescent tube of the starter type, i.e. with a glow-switch, which adds to the two conventional positions of all or nothing an intermediate position reduced, this intermediate position being controlled by any known means and being capable of being regulated.

The supply device according to the invention is characterized by the combination of:

(a) A normal ballast-resistance, single or double voltage;

(b) A leakage inductance of low power;

(0) A normal glow-switch, which is employed other than normally, that is to say having an output greater than that normally necessary for the tube employed;

((1) A contact means which can be servo-controlled, and which puts the said inductance in series with the said ballast resistance or short-circuits it.

When so required, the device according to the invention may further comprise a supply circuit for the tube electrodes, permitting its immediate re-ignition following a supply-voltage failure, irrespective of its operating condition during the interruption.

The invention will now be described with reference to the accompanying drawings, given by way of non-limitative examples. In these drawings:

FIG. 1 is a circuit diagram of one embodiment of the invention;

FIG. 2 is a circuit diagram of another embodiment of the invention.

3,526,806 Patented Sept. 1, 1970 Referring now to FIG. 1, the single-voltage device is supplied with single-phase alternating current, for example 22/0 volts at its terminals 1 and 2; between these terminals 1 and 2 are connected in series the fluorescent tube 3 with its glow-switch 4 in parallel, the leakage inductance -5 with a switch 6 in parallel, and the ballast resistance 7.

In this diagram, the electrodes of the tube 3 are continuously put under voltage, which has the additional advantage of prolonging the useful life of the tube. It is known that fluorescent tubes fail mainly because of their successive extinctions and ignitions. On the other hand, when the inductance 5 is short-circuited by the closed switch 6, the ballast 7 remains alone in service and the tube 3 supplies its full lighting, while when the open switch 6 inserts the inductance 5, the light intensity of the tube is considerably reduced. The invention makes it especially possible to maintain the arc voltage at a maintenance value just sufficient to prevent the interruption of the are, which would cause the extinction of the tube; it is then necessary to employ a starter 4 (glow-switch) having a power greater than that normally necessary for the tube considered, because the normal glow-switch would be too close to its striking and cut-off point and for this reason the tube could flutter.

Purely by way of indication, the applicant has obtained satisfactory results with the following characteristics:

For a tube of 20 watts supplied at 220 volts, the additional inductance was calculated to limit the light flux to, for example 10% of its normal value; the consumption when dimmed is than only 0.05 a. as compared with the consumption of 0.38 a. of the tube on normal working, and a glow-switch of 40 watts is necessary to avoid any liability to flutter in the dimmed position.

The auxiliary contact switch permitting the inductance 5 to be put into and out of service, can be constituted:

(a) either by any known devicea switch for the rooms of children or sick persons;

a clockwork or other timing device for corridors,

shops or cabins of lifts; a rotary or electronic system enabling blinking or light effects to be obtained for any duration and for any cyclic succession;

(b) or by a potentiometer resistance 8 permitting the value of the light flux to be controlled to any level within the range of light intensity.

This potentiometer could be combined with any of the known devices mentioned above and/or it may itself be servo-controlled so as to obtain any lighting effects by programmed variations within the range of light intensity.

For commercial reasons and considerations of practical use, the normal ballast resistance and its additional inductance can be combined in a single casing 9.

With the device according to the invention which has been described above, if the glow-switch tube is considered as working on the reduced rate and, due to a supply voltage failure or any other accidental cause, the supply current is interrupted, the tube will be extinguished while it is working on reduced current and in consequence it will strike badly or not at all when the supply current is restored. This absence of light could not be tolerated in certain cases, for example for reasons of safety, rapid action, etc., and in consequence the invention provides for the possible addition to the device already described of a separate circuit supplying the electrodes at constant intensity and constant voltage, enabling the tube to start again immediately after a supply voltage failure, and this will apply irrespective of the operating condition of the tube, extreme or intermediate, at the time of its accidental extinction.

Referring now to FIG. 2, there will again be found the parts already described, to which the same reference numbers have been given. In addition, there is added a separate transformer 11, the primary 12 of which is connected to the terminals 1 and 2 of the alternating current supply mains, and the secondaries 13 and 14 of which are each arranged as a heating source for an electrode 15 or 16 of the tube 3.

The assembly consisting of the ballast 7, the inductance and the transformer 11 can be housed in a single casing 19, as shown in FIG. 2.

The applicant has observed that a circuit for heating the electrodes, as described above, associated with a ballast and a glow-switch, actually and effectively constitutes a ballast for the tubes available in commerce under the descriptions rapid start, instantaneous, with striking strips, etc., with the result that, when thus completed, the all or reduced system becomes applicable to all tubes. It must however be observed that the normal glow-switch, employed other than normally forming the subject of one of the characteristics of the invention, remains necessary, since the breaking current which it causes is highly favorable to the good re-ignition of any tube which has remained in the reduced position.

On the other hand, it is well known that the striking or re-ignition of the above-mentioned commercially available tubes or the like proves very unreliable or even impossible when they are located in an ambient temperature higher than 50/55 C. It should furthermore be noted that the production of this critical temperature may be caused in time by the operation of the tube or tubes themselves when they are mounted in an air-tight apparatus, or with insuflicient ventilation, or with excessive heat insulation.

The applicant has observed that this drawback is eliminated by the device according to the invention, by virtue of the voltage surges produced at the tube terminals by the breaking current of the said glow-switch. In consequence, the invention also includes the presence of a normal glow-switch, utilized in a normal or other than age inductance of small output connected in series with said ballast device, and means connected in parallel with said inductance to short-circuit said inductance, said means including a switch connected in parallel with said inductance and a variable resistance connected in parallel with said switch and said inductance.

2. A device as claimed in claim 1, further comprising a transformer having secondary windings which are connected in series with the electrodes ofsaid tube to heat the same.

References Cited UNITED STATES PATENTS 2,296,062 9/ 1942 Scott 31510O 2,456,870 12/1 948 Francis et al 315-284 2,650,326 8/ 3 Williams 315-98 2,774,917 12/ 1956 Passmore 31597 3,383,554 5/1968 Oglesbee 315-284 X FOREIGN PATENTS 657,072 9/1951 Great Britain.

JAMES W. LAWRENCE, Primary Examiner C. R. CAMPBELL, Assistant Examiner US. Cl. X.R. 315-284, 289 

